628 



AKKAXGEMENT OF NERVE-CELLS. 



the cervical and lumbar enlargements. Ludwig and "Worschiloff constructed a series of curves 

 from measurements by Stilling of the sectional areas of the grey and white matter of the 

 cord, as well as of the several nerve-roots. These curves have been arranged in the annexed 

 convenient form by Schafer after "Woroschiloff (fig. 443)] : 



[In the cervical region, the lateral white columus are large, the anterior cornu of the grey 

 matter is wide and large, while the posterior cornu is narrow ; Goll's column is marked otf by a 

 depression and a prolongation of the pia mater ; the cord itself is broadest from side to side. In 

 the doreal region, the grey matter is small in animals, and both cornua are narrow and of nearly 

 equal breadth, while the cord itself is smaller and cylindrical. In it the intermedio-lateral 

 and posterior vesicular groups of cells are distinct. They have probably relations to viscera. 

 The commissure lies well forward between the crescents. In the lumbar region, the grey 



matter is relatively and absolutely greatest, while the white 

 lateral columns are small, the central canal in the com- 

 missure being nearly in the middle of the cord. In the 

 conns medullars, the grey matter makes up the great mass 

 of it, with a few white fibres externally (fig. 444).] 



The anterior cornu of the grey matter is shorter and 

 broader, and does not reach so near to the surface as the 

 posterior ; moreover, each anterior nerve-root arises from 

 it by several bundles it contains several groups of large 

 multipolar ganglionic cells (fig. 442) ; the posterior cornu 

 is more pointed, longer, and narrower, and reaches nearer 

 to the surface, the posterior root arising by a single bundle 

 at the postero-lateral fissure ; while the cornu itself contains 

 a few fusiform nerve-cells, and is covered by the substantia 

 gelatinosa of Rolando, which is in part an accumulation of 

 neuroglia. 



[The substantia gelatinosa on the posterior cornu is 

 marked by striation where the posterior root-fibres traverse 

 it. It contains some connective-tissue cells and some fusi- 

 form nerve-cells, especially near the margins. The substance 

 itself stains deeply with carmine.] 



[The outer margin of the grey matter near its middle is 

 not so sharply defined from the white matter as elsewhere ; 

 and, in fact, a kind of anastomosis of the grey matter pro- 

 jects into the lateral column, especially in the cervical 

 region, constituting the processus reticularis (fig. 446).] 



[Arrangement of Nerve-Cells. The nerve-cells are ar- 

 ranged in four groups, forming columns more or less con- 

 tinuous. There are those of the anterior and posterior 

 horns, those of the lateral column (intermedio-lateral), and 

 the posterior vesicular column of Clarke. The anterior and 

 posterior groups exist as continuous columns along the en- 

 tire cord. The cells in the anterior cornu are subdivided 

 into smaller groups, which vary in the different regions of 

 the cord. There is an inner or median group near the 

 anterior angle of the cornu. It is the smallest group, and 

 is absent in the lumbar region. Near the anterior edge is 

 the anterior group, and in the external part of the cornu is 

 the anterolateral group. These two groups are often 

 united, as in the mid-cervical region. There is usually a 

 third large group the external or postero-lateral in the 

 posterior outer angle of the anterior cornu the cells of the 

 anterior horn being very large (67 to 135 p); while the fusi- 

 form cells of the posterior horn are 18 /* in diameter. 

 Those of the lateral column are distinct, except in the lum- 

 bar and cervical enlargements, where they blend with the anterior horn. The column of Clarke 

 (ceils 40 to 90 /t) is discontinued, and is lim ited to (1) the thoracic reg ion, (2) cervico-cranial 

 region, (6) sacral region, being most conspicuous in (1), where it corresponds absolutely to the 

 f sfrir Z 1SC ? r ., ner Y es ( Gcuikel1 )- In 'the sacral region it corresponds to the "sacral nucleus 

 or stilling, while in the cervical region it begins in the dog at the 2nd cervical nerve, forming 

 tne cervical nucleus, being continued above into the nuclei of the vagus and glosso-pharvngeal 



iw e8 *rrf i ii I s thl8 column give rise to small medullated nerve-fibres or the leucenteric 

 fibres of Gaskell.] 



The multipolar ganglion cells are largest, and arranged in groups in the anterior horns of 

 the grey matter (fag. 446-" motor ganglionic cells "). [They also occur in the lateral process 

 ana in the processus reticularis. It is to be noted that the cells become more branched as we 



Fig. 444. 

 Transverse sections of the spinal 

 cord in different regions. A, 

 through the middle of the 

 cervical ; B, the dorsal ; C, the 

 lumbar enlargement ; D, upper 

 part of the conus medullaiis ; E, 

 at the 5th sacral vertebra ; F, 

 at coccyx; A, B, C, enlarged 

 twice; D, E, F, thrice; a, 

 anterior, p, posterior root. 



